How can I delete a movie?

Right now, you can't. Movies cannot be deleted, since there could be screenings or sources which point to the movie (even if there are none). Just edit the movie and change its name to any other movie.

I have two friends with the same name. How can the plugin distinguish between them?

Write your friend's names like Michael@SomeGuy1, Michael@SomeOtherGuy and so on. Only the part before the @ sign will be visible.